This invention relates generally to aroma-generators, and more particularly to a unit adapted to periodically discharge into the atmosphere bursts of aroma, the non-aromatic intervals between the bursts having a duration sufficient to avoid desensitizing the olfactory response of those exposed to the unit.
As used herein, the term "aroma" is not limited to pleasant or savory smells, but encompasses scents that function as insecticides, air fresheners, deodorants or any other odor that acts to condition, modify or otherwise charge the atmosphere.
The aroma of perfumes and perfume-based products such as colognes and toilet waters was originally derived from the essential oils of plants. However, since the early 19th century, chemists have succeeded in analyzing many essential oils and in creating thousands of synthetics, some simulating natural products and other yielding altogether new scents. Perfumes today are largely blends of natural and synthetic scents and of fixatives which equalize vaporization and enhance pungency. In most liquid scents the ingredients are combined with alcohol.
Various types of spray devices or dispensers are known for emitting aromas. Thus the patent to Dearling, U.S. Pat. No. 4,084,732, disclosed a dispenser for wafting into the atmosphere an insecticide, a pleasant smelling scent or any other aroma, this being accomplished by means of a pressurized container. When the actuating button of this container is pressed, a dispersant is released onto an absorbant material, the absorbent dispersant permeating the atmosphere.
Similarly, the Sekiguchi et al. U.S. Pat. No. 3,679,133 discloses a perfume dispenser which includes a spongelike head that receives and exudes a charge of perfume. In the spray aerosol can disclosed in the Harrison U.S. Pat. No. 3,972,473, an absorptive ring is impregnated with an air-freshening fragrance and released into the atmosphere. U.S. Pat. Nos. 1,921,821; 3,410,488; and 3,441,353 are along similar lines, for they show wicks and other absorptive materials to accept and emit a perfume or other odoriferous liquid.
In my prior U.S. Pat. No. 4,200,229, entitled, "Aroma-Dispensing Cartridge and Holder Assembly," the assembly is designed for installation in an automobile interior for charging this interior with a pleasant or stimulating fragrance. The cartridge includes a bottle filled with a liquid scent, a suction pump being supported on the stopper of the bottle. When actuated, the pump sprays the scent onto a pad of absorbent material.
The difficulty with an aroma dispenser which functions to spray a charge of liquid onto a pad of absorbent material is that at ambient temperature the liquid, even when it has a high alcohol content, is slow to volatilize; hence the resultant odor, though of sufficient strength in the confines of an automotive interior, may lack adequate intensity in those environments which are relatively open, such as the living room or bedroom of a home.
It is known to promote vaporization of aroma-producing liquids by means of an electric bulb which also generates heat. Thus the Eisner U.S. Pat. No. 2,372,371 shows a pad saturated with a deodorant held in a small container mounted directly on the bulb. Similar bulb arrangements to promote vaporization are disclosed in the Gudeman U.S. Pat. No. 1,403,548; the Fusay et al. U.S. Pat. No. 2,557,501; and the Schlesinger U.S. Pat. No. 2,435,756. Also of background interest are the prior patents cited in my above-identified copending application now U.S. Pat. No. 4,346,059.
In my copending patent application, there is disclosed an aroma generator in which a pad of porous material impregnated with an aroma-producing liquid is disposed under a vent inm a substantailly enclosed housing. An electrical heating element placed in the housing acts to heat and expand the air confined therein to create a positive air pressure producing a pressure differential between the heated air and the atmosphere above the vent, as a consequence of which the heated air is driven through the pad to rapidly volatilize the liquid and exude an aromatic vapor through the vent into the atmosphere.
The olfactory organs are chemi-receptors which are stimulated by minute quantities of gases or vapors in air as low as one part in one million of air. The olfactory cells are connected with the brain by the fibers of the olfactory nerves. The perception of smell by an individual's brain is such, that if a given smell persists, the individual ceases to be aware of the smell, for he makes an accomodation to the odor which is then treated as the prevailing environment. Thus one who first enters a hospital environment becomes immediately conscious of an antiseptic odor, but his sensitivity thereto diminishes and virtually disappears if the individual remains in this environment. When, however, he leaves the hospital and is exposed to the outside atmosphere, he quickly senses this change.
Thus the operation of the olfactory system is such that it is highly responsive to a change in the nature or level of an aroma but is desensitized when the prevailing odor attains a steady state condition. Hence in a room having an aroma generator of the type disclosed in my copending application in which an aromatic vapor is continuously exuded, persons in the room subjected to the vapor cease in time to become aware of the aroma, and the generator, even though it continues to operate, serves no useful purpose.